Добавьте это в htaccess:
<ifModule mod_deflate.c>
AddOutputFilterByType DEFLATE text/html text/plain text/xml application/xml application/xhtml+xml text/css text/javascript application/javascript application/x-javascript
</ifModule>
<IfModule mod_gzip.c>
mod_gzip_on Yes
mod_gzip_dechunk Yes
mod_gzip_item_include file \.(html?|txt|css|js|php|pl)$
mod_gzip_item_include mime ^text\.*
mod_gzip_item_include mime ^application/x-javascript.*
mod_gzip_item_include mime ^application/javascript.*
mod_gzip_item_exclude mime ^image\.*
mod_gzip_item_exclude rspheader ^Content-Encoding:.*gzip.*
</IfModule>
<ifModule mod_headers.c>
<filesMatch "\.(ico|jpg|jpeg|png|gif|swf)$">
Header set Cache-Control "public"
</filesMatch>
<filesMatch "\.(css)$">
Header set Cache-Control "public"
</filesMatch>
<filesMatch "\.(js)$">
Header set Cache-Control "public"
</filesMatch>
<filesMatch "\.(x?html?|php)$">
Header set Cache-Control "private, must-revalidate"
</filesMatch>
</ifModule>
<ifModule mod_expires.c>
ExpiresActive On
ExpiresDefault "access 7 days"
ExpiresByType image/x-icon "access plus 6 month"
ExpiresByType image/jpeg "access plus 6 month"
ExpiresByType image/jpg "access plus 6 month"
ExpiresByType image/png "access plus 6 month"
ExpiresByType image/gif "access plus 6 month"
ExpiresByType application/x-shockwave-flash "access plus 6 month"
ExpiresByType text/css "access plus 7504800 seconds"
ExpiresByType text/javascript "access plus 7516000 seconds"
ExpiresByType application/javascript "access plus 7516000 seconds"
ExpiresByType application/x-javascript "access plus 7516000 seconds"
ExpiresByType text/html "access plus 600 seconds"
ExpiresByType application/xhtml+xml "access plus 600 seconds"
</ifModule>
